NOS – Joris van Poppel
NOS Nieuws•vandaag, 17:14
Francien Intema
Domestic editor
Francien Intema
Domestic editor
Will the midges that spread the bluetongue virus in the Netherlands disappear this winter? Or will they still be present in stables, for example? The Dutch Food and Consumer Product Safety Authority (NVWA) has started an investigation to get an answer to this. While the researchers are catching the mosquitoes, they are already seeing that their numbers have dropped in recent weeks.
At the beginning of last month it was announced that bluetongue is in the Netherlands. The virus spread by midges currently mainly affects sheep and cattle. It has now been identified at 3,000 locations and, according to outgoing Minister of Agriculture Adema, thousands of sheep die in the Netherlands every day. A working vaccine is not yet in sight.
Blood-sucking species
To know how to do something about the spread of the virus, it is important to find out which midge species spread bluetongue. In the Netherlands there are forty species of midges that suck blood and can transmit pathogens. The NVWA expects that only a small part of these are involved in this bluetongue outbreak.
It is not known exactly which species spread this bluetongue variant. That is why the NVWA went to ten affected companies in recent weeks to catch midges. In the lab, insect experts look at tens of thousands of animals through a microscope to see which species fell into the trap. Scientists in the laboratory of Wageningen Bioveterinary Research then investigate which species carry the bluetongue virus.
See how the research works here:
NVWA is investigating midges that spread bluetongue among cows and sheep
Yesterday, the NVWA started placing new traps to monitor the numbers of midges in the near future. Traps occur at about five farms: one outside in the yard and one inside the stable.
Veterinary microbiologist Mathilde Uiterwijk from the NVWA empties the traps every day and the lab checks which species they are and whether they are infected with bluetongue. This should make it clear how long the virus spread lasts in the winter.
Breeding grounds
The real solution to this outbreak is a vaccine, experts say. But the NVWA hopes that this research can slow the spread somewhat. “Some midge species reproduce in the manure, other species do so in the soil,” says NVWA entomologist Arjan Stroo. If you know where the virus spreaders breed, you may be able to reduce the numbers.
“We also want to know whether those midges occur as much indoors as outdoors,” says veterinary microbiologist Uiterwijk. “Does it make sense to bring livestock inside, or do the same species of midges occur there in the same quantities and is there therefore not much point?”
See below where bluetongue has been diagnosed:
NOS
Farmers’ organization LTO Netherlands is not looking forward to the research. “Scientifically it will be very useful, but we have other priorities at the moment,” responds Saskia Duives, chair of the sheep farming department of the trade association. “For me, this research is not necessary. A vaccine must be available quickly, and the minister must allocate money for that.”
The research does indeed not prevent outbreaks, Uiterwijk acknowledges. “More insight into which midges are relevant can help to better predict outbreaks and, for example, to know which possible diseases we should take into account in the future. Such information can help the sector to prepare for this. It also provides information about which measures are useful.”
When placing and emptying the traps, the NVWA researchers already noticed that the total number of midges has decreased in recent weeks and experts expect that the cold will reduce the number of infections with bluetongue. The knowledge gained from the research will therefore make the biggest difference in the spring, when temperatures rise and the midges become more active.
2023-10-24 15:14:38
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